Why is the since and until parameter in instagram-business-discovery in instagram-graph-api seems to be inconsistent with all timestamp values?

I'm encountering an issue with retrieving Instagram posts using the Facebook Graph API. When I use recent timestamps within a month, the following code works fine:

graph.facebook.com/v19.0/{instagram_business_account}?fields=business_discovery.username({ig_user_id}){media.since(1704477217).until(1714477219){timestamp,caption}}&access_token={access_token}

However, when I attempt to use older timestamps, even though the time interval (difference between since and until) remains the same, the request doesn't return the expected results.

For instance:

graph.facebook.com/v19.0/{instagram_business_account}?fields=business_discovery.username({ig_user_id}){media.since(1672834201).until(1672835201){timestamp,caption}}&access_token={access_token}

Despite being certain that there's a specific post at that interval of time, the API doesn't seem to return it.